compound assignments require usual arithmetic promotions

Daniel Kroening · Daniel Kroening · commit e78e7d105c7e · 2019-01-08T12:42:38.000Z
The C frontend needs to apply the usual arithmetic promotion rules in compound assignments. Fixes #3706.
diff --git a/regression/cbmc/compound-assignment/compound_promotion.desc b/regression/cbmc/compound-assignment/compound_promotion.desc
@@ -1,5 +1,5 @@
-KNOWNBUG
-compound_promition.c
+CORE
+compound_promotion.c
 
 ^EXIT=0$
 ^SIGNAL=0$
diff --git a/src/ansi-c/c_typecheck_expr.cpp b/src/ansi-c/c_typecheck_expr.cpp
@@ -3459,7 +3459,7 @@ void c_typecheck_baset::typecheck_side_effect_assignment(
     }
     else
     {
-      implicit_typecast(op1, o_type0);
+      implicit_typecast_arithmetic(op0, op1);
 
       if(is_number(op1.type()) ||
          op1.type().id()==ID_bool ||

Original file line number	Diff line number	Diff line change
`@@ -3459,7 +3459,7 @@ void c_typecheck_baset::typecheck_side_effect_assignment(`
`3459`	`3459`	`}`
`3460`	`3460`	`else`
`3461`	`3461`	`{`
`3462`		`- implicit_typecast(op1, o_type0);`
	`3462`	`+ implicit_typecast_arithmetic(op0, op1);`
`3463`	`3463`
`3464`	`3464`	`if(is_number(op1.type()) \|\|`
`3465`	`3465`	`op1.type().id()==ID_bool \|\|`